ProgramNode(0...8)(
  [],
  StatementsNode(0...8)(
    [CallOperatorWriteNode(0...8)(
       CallNode(0...3)(
         CallNode(0...1)(nil, nil, (0...1), nil, nil, nil, nil, 0, "a"),
         nil,
         (1...3),
         (1...2),
         nil,
         (2...3),
         nil,
         0,
         "[]="
       ),
       (4...6),
       CallNode(7...8)(nil, nil, (7...8), nil, nil, nil, nil, 0, "b"),
       :+
     )]
  )
)
